Tubing



Oct. '31, 1933. B, QUARNSTROM TUBING Filed Oct. 6, 1931 4 2 Sheets-Sheet1 I INVENTORQ BERT L. QUARNSTROM A TTORNEYS 0 31, 193 B. L. QUARNSTRQMTUBING 2 Sheets-Sheet 2 Filed Oc t. 6, 1931 l NV EN TOR.

A TTORNEYS.

Patented Oct. 31, 1933 TUEEKNG Evert ll..- Quarnstrom, Grosse PointePark, Mich... assignor to Bandy Tubing Company, Detroit, Mich acorporation at Michigan Application October 6, i931.' Serial No. 567,321

% Claims.

This invention relates to tubing, and it has to do particularly with atube of improved conmovement.

struction which is made from strip stock fashioned into tubular form andhaving'its edges united to form a strong and effective seam.

The invention is one which lends itself advantageously to the making oftube from strip stock wherein the strip stock is fashioned through 360thus giving the tube a single ply wall. Accordingly, drawings showing atube having a single ply wall are utilized for this disclosure, but itis understood that the invention is applicable to tubes having multi-plywalls.

A tube of a single ply wall constructed in accordance with the inventioncomprises a strip shaped into tubular form with its edges overlappingand secured together; this type of tube made from strip stock iscommonly termed a lap seam tube. The object of the invention is toprovide an improved lap seam structure wherein the edges are lockedtogether. The structure is such as to materially strengthen the tubeinasmuch as the locking arrangement prevents the edges from separatingby relative movement circumferentially of the tube, and also by relativeradial A number of things may tend to cause'such separation, such aspressures on the tube either internally or externally, or by the bendingof the tube into suitable shapes. As a more specific example, highinternal pressure may tend to separate the edges by relative,circumferential movement. In accordance with the invention the edges arelocked together to oppose such movement. Prior to separation by relativecircerential movement, relative radial movement of the edges may benecessary to permit oi relative circumferential movement, but inaccordance with the invention the edges are locked together to preventthis relative radial movement.

In the accompanying drawings:

Fig. l is a transverse sectional view taken through a strip oi! stockshowing the same as it may appear after the first operation in themaking of the tube.

Figs. 2 to 6, inclusive, show one way in which the strip stock may berolled or fashioned into tubeiorm by means of suitable forming rollsknown in the tube making art.

Fig. 7 is an enlarged sectional view taken through the edges prior tothe final operation.

Fig. 8 is an enlarged sectional view showing the completed lapped andlocked seam.

Fig. 9 is a sectional view in illustration of (Gi. Hal- 35 formingrollers which may be used for suitably shaping a strip into the formshown in Fig. i.

Fig. 10 is a sectional view illustrating rollers and arbor which may beemployed in making the tube just prior to the final operation.

Fig. 11 isa similar view illustrating rollers and arbor which may beemployed in the final opera tion.

A strip of material, of which the tube may be made, may be, in a longlength and disposed in a roll from which'it may be drawn by longitudinalmovement and fashioned and shaped into tube form by tube forming rollerssuch as are known in the tube making art. Such strip may be 0i uniformthickness from edge to edge, and the thicknessand width may be selectedas desired for making tubes of diiierent requirements. The strip may befirst acted upon to shape it substantially as shown in Fig. 1. This maybe done by means of rolls, as shown in Fig. 9, wherein the strip isreferenced 1 and opposed rolls are at 2 and 3.

These forming rolls may be termed pressure rolls between which the stripmay be drawn. The space between the rolls in their central portions maybe such as to be substantially equal to the thickness of the stock; theroll 2 may have a fillet 4, a groove 5, a raised portion 6, and a part 7the diameter of which may be slightly greater than the central portionof the roll. Roll 3 may have corresponding parts such as fillet 8,groove 9, raised portion 10 and part 11. As the strip passes throughthese rolls the said parts cooperate to flow the metal of the strip andshape the same, as shown in Fig. 1. The 99 raised portions 6 and 10compress and flow the metal to form grooves near the edges of the strip,as shown at 15 and at 16. In doing this the metal is compressed and someof the same fiows into the grooves 5 and 9 thus forming projections 1'!and 18 immediately adiacent the grooves 15 and 18. The parts 7 and 11 ofthe rolls may compress the extreme edges of the stock thus thinning themand forming parts 19 and 20,

while the fillets 4 and 8 form angular or beveled 10o edges 21 and 22.In thus shaping the strip it is preferable that the thickness of themetal forming the bottom of one of the grooves plus the thickness of themetal forming one of the edge portions 19 and 20, is substantially equalto the initial thickness of the strip stock, or in other words, equal tothe center or body portion of the strip.

After thus fashioning the strip the same may then pass through theforming rolls of a tube lit) .of the strip following the second bendingoperation; Fig. 4 illustrates the shape the strip may take following thethird bending operation; Fig. 5 illustrates the relation of the parts ofthe strip and the shape of the strip following the fourth bendingoperation; while Fig. 6 may illustrate the final form of the tube.Inasmuch as the tube making machines embodying tube forming rollers areknown in the art it is not deemed nee-v essary herein to show suchmachine as the manner in which tube is constructed by the machines iswell known to those versed in the art.

By referring to Fig. '7, it will be noted that the portion 19 is fittedinto the groove 16 whereas portion 20 is fitted into the groove 15.Advantageously and preferably the formation of the strip is such thatthe inner edge of the portion 19 and inner edge of the portion 20 aresubstantially at right angles to the body of the strip so that these twoedges form an effective engagement with each other when they are fittedtogether as shown in Fig. 7. It is advantageous that the parts 19 and 20fit rather snugly in the grooves 16 and 15 when in the condition shownin Fig. 17. The engagement may be rendered still more snug or tightafter pressure has been applied for finally shaping the partsas shown inFig. 8 by means of flowing the metal. It will be noted thatthe bevelededge 22 lies next adjacent projection 18, and the bevel edge 21 liesnext adjacent the projection 1'7. These projections 17 and 18 are thenurged or fashioned against the respective beveled edges substantiallyfilling the groove formed thereby, and'due to their overlapping thebeveled edges, serve to lock the parts togetherto prevent separation ofthe overlapped edges of the strip by relative radial movement. In Fig.10 a pair of rolls and an arbor are shown such as may be employed whenthe tube and its seam are in the condition shown in Fig. 7. The pressurerolls are illustrated at 30 and 31, respectively, one of which has agroove 32 for accommodating the projection 18. Inside the tube is anarbor 33 having a groove 34 for accommodating the projection '17. InFig. 11 there is shown another set of rolls and another portion of thesame arbor 33 such as may be employed for fashioning the projections 17and 18 into locking position. These rolls are shown at 35 and 36,respectively, and are shaped to engage the tube structure over itssurface while the arbor 33 at this point does not have the groove 3i.vThus the arbor fashions the projection 17 into its final position, andthe roll 35 fashions the projections 18 into final position as the tubeis drawn or moves through rolls and over the arbor. It is to beappreciated that the rolls 35 and 36 may exert considerable pressureupon the tube and that the arbor provides internal reinforcement,exerting requisite outer pressure for shaping the projection 17 and forsupporting the tube.

It will be seen that a tube thus constructed has a seam wherein theedges are lapped, and at the same time locked together. An eflectivelock is provided by the interfitting of the projections 19 and 20 andthe grooves 15 and 17. To further strengthen this lock and to preventseparation of the edges, projections 17 and 18 are thrown down overopposite edges of the stock. By coordinating. the depth of the grooves15 and 16 and the meagre thickness of the portions 19 and 20 the wallthickness of the tube at the seam may be substantially equal to thestock thickness. When the portions 17 and 18 are fashioned into finalposition both the inside and outside surfaces of the tube are completedinto a smooth substantially unbroken surface.

Various kinds of metals may be selected in making this tube, and theseam may be sealed by the utilization of molten sealing metal of anydesirable type. Also the edges of the strip may be welded without theuse of an intermediate sealing metal. The seam and all overlapping partsmay be sealed by the means of solder such as the common tin and leadalloy, or various other solders such as silver-solder or the like, orbrazing metal. Copper may be used for sealing the seam as well as forcoating the tube inside, outside, or both, and in this regard it may bepointed out that the copper sealing and coating medium may be employedwith strip stock of ferrous metal. Of course the copper may be employedwith strip stock of other metals, but where ferrous metal is used it maybe desirable to coat the same and seal the seam with copper. It may alsobe pointed out that while the strip for forming the tube hereindescribed is fashioned into appropriate form by pressure rolls, asillustrated in Fig. 9, the strip may likewise be fashioned by cutting ortrimming operations without departing from the scope of the invention.The resultant tube is one having a strong, single .ply wall with a seamwhich afiords substantiallyunbroken and smooth interior and exteriortube surfaces, and which aifords great strength for resisting rupture orbreakage. While it is preferable that the seam be sealed by molten metalor by welding for the purpose of conducting fluids or the like,structural tubing may be made and used without sealing the seam againstfluid leakage as the seam structure affords material strength evenwithout being thus sealed.

I claim:

1. A tube comprising a strip of metal fashioned into hollow crosssectional form with the edges 1;?

of the strip overlapping and providing a seam lengthwise of the tube,each edge having a groove and an adjacent projecting portion, with thegrooves and projecting portions of the respective edges interlockingwith each other, and means on an edge overlapping the other edge forlocking the edges against separation by relative radial movement.

2. A tube comprising a strip of metal fashioned into hollow crosssectional form with the edges of the strip overlapping and providing aseam lengthwise of the tube, each edge having a groove and an adjacentprojecting portion with the grooves and projecting portions of therespective edges interlocking with each other, each edge having anotherprojecting portion overlapping the opposing edge for locking the edgesagainst separation by relative radial movement.

.3. A tube having a longitudinally running seam comprising a strip ofmetal fashioned into hollow cross sectional form with the edges of thestrip overlapped, one on the inside and one on the outside, said edgeshaving cooperating grooves and projections which interflt to form alocking engagement, the edge of the strip on the inside of the overlaphaving a part which overlaps the outside of the opposite edge.

4. A tube comprising a strip of metal fashioned into hollow crosssectional form with the edges of the strip overlapped, one on the insideand one on metal of the edge forming an abutment defining the outside,said edges having cooperatin grooves and projections which interfit toform a locking engagement, theedge of the strip on the inside of theoverlap having a part which overlaps the outside of the opposite edge,and the edge of the strip on the outside of the overlap having a partwhich overlaps the opposite edge on the inside of the tube.

5. A tube comprising a strip of metal fashioned into hollow crosssectional form with the edges overlapping, each edge having alongitudinal groove bounded by an abutment with said grooves andabutments interfitting to lock the edges together, the edge of the stocklocated inside the tube having a longitudinal part disposed so as tooverlap a portion of the opposite edge on the outside of the tube, andthe edge of the stock located outside the tube having a longitudinalpart disposed so as to overlap the opposite edge of the stock on theinside of the tube..

6. A tube having a longitudinally running seam comprising a strip ofstock fashioned into hollow cross sectional form with its edgesoverlapping, said edges having interfitting grooves and projectingportions to lock them together against separation by relativecircumferential movement, said edges at their extreme ends having each abeveled portion, and each edge having a longitudinal projectionfashioned into overlapping relation as regards the beveled portions.

7. A tube comprising a single strip of metal stock fashioned into hollowcross-sectional form having a longitudinally running seam, one face ofthe stock having a longitudinally running groove adjacent one edge ofthe stock with the one side of the groove, the metal defining theopposite side of the groove having a longitudinally running projection,the opposite face of the stock having, adjacent the opposite edge of thestock, a similar groove defining abutment and longitudinally runningprojection, the edges of the stock being lapped one over the other withthe abutment forming metal of each edge fitted into the groove of theother edge,and the longitudinally running projections overlying portionsof the edges fitting into said grooves to lock the same in the grooves.

8. A tube comprising a single strip of metal stock fashioned into hollowcross-sectional form having a longitudinally running seam, one face ofthe stock having a longitudinally running groove adjacent one edge ofthe stock with the metal of the edge forming an abutment defining oneside of the groove, the metal defining the opposite side of the groovehaving a longitudinally running projection, the opposite .face of thestock having, adjacent the opposite edge of the stock, a similar groovedefining abutment and longitudinally running projection, the edges ofthe stock being lapped one over the other with the abut ment formingmetal of each edge fitted into the groove of the other edge, the ertreme edgesof the stock being. relieved from opposite faces of thestock and the longitudinally running projecspective relieved portions ofopposite edges to lock the same in the grooves.

BERT L. QUARNSTROM.

tions adjacent'the said grooves overlying the re-

